In a vehicle security system the method of deactivating is almost always by means of a coded key. The coded key may be a radio remote, a proximity device or a contact type such as a plug which is inserted into a socket. In order to offer security the number of codes should be high. In most modern security systems taking into account various encryption methods, the number of different codes can effectively be in the billions. Often the coded key is provided as a binary code which is serially transmitted to an immobiliser or car alarm. In modern security systems a transmitted code can have 64 bits, and taking into account various encryption methods, the number of different codes can be in the billions. In addition there is a system of encryption which uses “code-hopping”, where the transmitted code has a portion thereof which increments by a predetermined amount determined by an algorithm in the coded key. The immobiliser responsive to the coded key incorporating the code-hopping technology includes a processor which is able to predict ahead a large number of increments, so that the immobiliser remains responsive to the coded key in the event that the coded key is caused to transmit several increments out of range of the immobiliser.
The security system is, in normal use, responsive to a unique allocated user code, so that the security system can be disabled and enabled by the owner of the vehicle in which it is installed. This user code is determined and programmed into the coded key during manufacture, and into the security system either during manufacture or alternatively the security system can learn the user code from the coded key, by placing the security system into a learning mode.
Motor vehicle dealers usually have many cars at one time in their car yard. The typical practice is to have the keys to the vehicles stored in a central secure location, such as in the sales office. Staff wishing to demonstrate a vehicle to a potential customer must retrieve the keys and any coded key remote control (or other type of coded key) for the vehicle beforehand.
It is an object of this invention to provide a system and method that can provide security to vehicles in a car yard or like establishment, and obviate the above difficulty.
Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.